Tandem spring suspension unit



TANDEM SPRING SUSPENSION UNIT 2 SHEETS-SHEET 1 Filed July 5, 1950 m 0; U Wm- Q m unw- 3 LL Van L. Frazier INVENTOR.

Dec. 4, 1951 v. FRAZIER TANDEM SPRING SUSPENSION UNIT Filed July 5, 1950 2 SHEETSLSHEET 2 a m W A 'l/ h y/ r V a. v m a w V. B N t Patented Dec. 4, 1951 TANDEM SPRING SUSPENSION UNIT Van L. Frazier, Springfield, Mo., assignor to Frazier Tandem Systems, Incorporated, Springfield, Mo., a corporation of Missouri Application July 5, 1950, Serial No. 172,114

12 Claims. 7 1

This invention relates to new and useful improvements in tandem spring suspension systems or units, and more particularly pertains to improvements over my Patent No. 2,455,989, issued December 14, 1948.

The primary object of the instant invention is to provide a tandem spring suspension system to equalize axle loads, and in which each axle travels vertically relative to the frame in spaced identical paths of travel to afford a superior and more even braking action and load distribution.

Another important obiect is to provide'a spring suspension system of this character which may be secured either to the sides or below the frame of the vehicle, and the use of any particular system assembly will not be limited by the width of the frame with which the same is to be associated.

Another important object is to provide a system of this character that is resistant to wear, and

.in which the maximum interchangeability of parts is attained for the reduction of the cost of manufacture, as well as permitting ease of replacement and repair.

A meritorious feature of the present invention resides in the provision of torque arms which extend in the same direction and in parallel relation from the brackets or axle mounting means on the springs to which they are pivoted,"and that a pair of such torque arms are adjustable in length to permit adjustment of the system.

Another important feature of the present invention resides in the provision of equalizers pivoted on stub shafts fixedly carried in equalizer housing brackets, and the bearings and lubrication means provided therefor.

A further feature of the present invention resides in the provision of a perch on the equalizer housing bracket for preventing the spring from jumping out of the equalizer.

Still another important feature of the present invention resides in the provision of means on the equalizer housing bracket for alternatively pivotally mounting the forward end of the rear adjustable torque arm or the forward end of the rear rigid torque arm.

Yet another important feature of the present invention resides in the provision of the beveled wearing surfaces in the spring hangers.

A final important feature to be specifically enumerated herein resides in the provision of the forward spring hangers extending forwardly and downwardly so that both axles will have the same radius of action.

These, together with various ancillaryfeatures and objects of the invention which will later of Figure 1;

Figure 3 is a side elevational view of a modified form of the means for mounting the springs on a differently shaped axle;

Figures 4 and 5 are views showing alternative means for securing the forward spring hangers to a vehicle frame, which means obviously may also be applied for mounting the equalizer brackets and the rear spring hangers on the vehicle frame; and.

Figure 6 is a perspective view of a rigid torque arm that may be substituted for the adjustable torque arms shown in Figure 1.

Reference is now made more specifically to the accompanying drawings, wherein like numerals designate similar parts throughout the various views, and in which the numeral [0 designates the left hand portion of the tandem spring system or unit generally, it being understood that a similar right hand portion will be employed therewith in use.

The system H) includes an equalizer housing bracket designated generally at l2, which, as shown in Figure 2, is a one-piece casting and consists of a pair of side walls l4 and I6 connected at their upper edges by a plate l8 and at their lower edges by a perch 2!! to be more fully described hereinafter. However, it will be understood that the bracket l 2 may be fabricated from separate pieces of material. A stub shaft 22 removably extends through the side walls l4 and I5, and which stub shaft 22 is releasably secured in the bracket [2 by means of a removable equalizer shaft bolt 24 through an annular boss 26 formed on the side wall l6, said bolt 24 being retained by a nut, not shown.

-An equalizer 28 is pivotally mounted in the bracket l2, which equalizer includes oppositely extending arms 30 which carry spaced depending flanges 32 to constitute inverted U-shaped housings for the adjacent ends of springs 34 and 36. The central ortion of the equalizer 28 is provided with a transverse opening 38 which receives the stub shaft 22 to journal the equalizer on the shaft 22, and spaced needle bearings 48 are provided in the opening 38 surrounding the shaft 22.

Means is provided to lubricate the bearings All which includes an L-shaped lubrication passage 42 in the shaft 22 communicating-with thezspa'ce between thebearings 4B and a greasefitting 44 is provided for the introduction of lubricant thereinto.

The remote ends of the springs :3 and11iii:a-re received in inverted U-shaped spring hangers 45 and 48, respectively. In order toreduce'wear on the ends of the spring, the 'sprin'g hangers 46 and i 48 are provided with beveled wearing surfa'cesbll, while the equalizer arms 30 are gprovideid with detachable wear plates 52. i

In order to prevent thesprings beingjarred out of position with respect to the equalizer, bolts 54 extend fthroughtbeffiangessz which carry-rollers 3.56 between thefflanges, while the spring r hanger '48 fistlikewise provided with a pin 58 "and :a roller as 'Lfor1preventing Tthe spring 35 being jarred out of lthe spring hanger 48. However, it will he understood that bars could be provided "in lieu of sueh pins and rollers that would be cast fintegrallywith the spring hangers, such-as thebar E?! form'ed w'ith the spr'ing'hanger 46.

Springehairs B2 and 5'4 are provided for the springs 34 and "36, respectively, which are deta'chably clamped to the springs by means of U-"bolts -66 disposed on "seats 61, such spring chairs includin upper plates 68 and lower'c'lamp- *ingplaites fis'adapted to clamp the axles lit -therebe'tween, the plates ts being interposed -between the springs and the axles, it being understood that the thickness of the plates 68 will deterniine the spacing of the axles "below the central "portion -of the springs.

An adjustable "torque arm 72 connects the equalizer housing bracket 12 to the spring chair associated with the spring 36, the forward end -of which is p'ivoted'on apivotbolt 74 extending I th'roug'h spaced legs '16 depending'ly "carried *by the perch 2B and sidewalls "I 4 and 1 6, as is clearly shown fin Figure 2. Tapered resilient "bushings 38 are provided in the pivotal connection "to re- "duce bOth -wear and vibration. The rearend of the torque arm 12 is bifurcated to receive an aper'tured p'ivotear on the plate '68 and is "pivotally connected *thereto "by a pivot bolt 813.

'Tl he'forward spring hanger 16 includes spaced,

forwardly and downwardly extending'legs 8'2,be-

tween the lower extremities of which is -'received the forward end of an "adjustable torque arm 284 "that *is pivotally connected "thereto by means of a bolt 6, it beingunderstood that resilient tapered bushings may be provided in this pivotal connection if desired. As with the adjustable torque arm 12, the rear end of the torque arm 8's *is bifurcated and pivotally connected to th'e plate -68 of the springbhair 62 by 4 lent action of the spring assembly on braking action of the vehicle.

It is of paramount importance that the torque arms l2 and 84 both extend forwardly from the spring chairs, or at least that the torque arms extend in the same direction therefrom, so that, upon braking action, both the torque arms are either silaced =is'imultaneously under compression or tension and "the axles -ifl tend to rise o fall together, so that during braking action the load distribution on the axles will tend to be identical.

,Asblearlyishown in Figure 1, the perch 29 extends forwardly and rearwardlly from the equalizer housing 'bracket l2 so as to be below "the adjacent en'ds "of the springs for the purpose *'of-preventing the springs from jumping or being displaced:from ,the oppositely extending arms 30 of the equalizer.

will be understood that the spring chairs 62 and 64 may be modified to secure the springs to axlesfthat fare irregularly shaped rather than moundgandeins-Ffigurefi :therevisshown .a modified spring chair *plate and clamping plate .92 'which ibee'n #shaped -to conform to the 'TClOIlfiQllI'ttion of an axle 9d of an I-shap' iinicrioss section. litnzimportantradvantageiof the present invenztionwesides :in the slant that the equalizer :hous ing braeketzl'i zias swell as the spring hangers "i6 rand fii? may :be "secured to the side as well as the :bnttom ref :the iframe of the :vehicle 'with which ,thelspring :systemis associated, 311d illustrative xrfithiszfact=there-islillustratedin Figures iel "and 5 alternative means :by which th'e forward isprin'g manger it may lriessemired to the frame :85 f theyehicle. 'JIn'Figure 4, "the spring shanger as is shblwnaasi beingss'ecured toitheibottomfoi their ame 5,2thisbe'ing 'aecomplishe'dibyfwelding or otherwise suitably securing a formed angle as to both :96 ::and ithe spring :hanger E5, while in figured zthe spring lhangeriis shown :as being secured ts @the side of the frame 95, this being accomplished iby :means of a gusset plate ma welded orsotherwisetsuitablyisecured Ito 't'he.;rrame 96 and the spring hanger. V

:Onerof the primary :advantages .of zthe present invention stems :-from the :fact that no cross "bars are requiredwhatsoever :between the .spring sys- EtEIIlSXOIlDDPdSi-te sides of the vehicle Iirame,'- itbe means *of -a;pivot bolt 88. ltfisiimportant'to note that the legs 82 of *ther'spr'in'g hanger 4.5 extend forwardly and downwardly so that the torque arms 12 and $18.4 ,may ,be of ,the same length; so that when the axles 1d .are positioned centrally with respect .to the springs with which they .are associated, and upon rocking movement of the equalizer 28, the axles 1.0 will, alternatively move on vertical fares thatare identical. .This fact con'tributes -materially "to the equalization .ing uh'derstood thatra separate spring system Ill, such *as illustrated in Figure 1, is to be used 'on each (if the opposite'sides o'fthe vehicle .frame, s0 that the #use of any particular spring system isindependent of the' width of the frame to which itis tc he 'conniected. However, :as "illustrative of the fact that cross bars'or ties may be utilized-between corresponding spring hangers, as well as between the corresponding equalizer 'housing 'bracketpthere is shown in Figures 4 and '5 cross bars HIZ su'itably secured 'to the spring hangers 46, which, it will be un'ders"tood, are secured-at their Kilih'l ends, to -'a :corresponding spring hanger ion @the opposite side of the frame.

' While'thespringsuspensionunit :12 has been shown as equipped with adjustable torque arms, in use it mas been found "preferable that only the spring suspension unit on the'right hand or curb 'si'deiof the vehicle frame be equippedwith adjustable Ftorque :rods, while the left hand spring unit is equipped with rigid torque arms such as shown-at ZI M'in Figure 6,it being understood that the adjustable and rigid torque'arms are 'completely' interchangeable in the spring suspension system, "Ihe righ't hand unit is equipped with adjustable torque arms primarily for the reason of the iload'ontthe :axles lilllandrafiordstanlexeelthat the .right hand side of the vehicle takes However, since numerous same interchangeable with either of the torque arms 12 or 84. I 7

As described, it will be appreciated that the spring system may be eflicaciously adjusted by means of the adjustable torque arm 12, and in the preferred construction, since the spring and the spring chairs are identical; the maximum interchangeability of parts is attained. 1

Since," from the foregoing, the construction and advantages of this device are readily apparent, further description is believed to be unnecessary; v

modifications and equivalents will readily occur to those skilled'in the art after a consideration of the foregoing specification and accompanying drawings, it is not intended to limit the invention to the exact embodiment shown and described, but all suitable modifications and equivalents may-be resorted to which fall within the scope of the appended claims. A

Having described the invention, what is claimed as new is:

1. In a tandem spring suspension unit; an equalizer housing bracket comprising a housin opening at opposite ends and including a pair of spaced side walls, a stub shaftextending between the side walls, an equalizer centrally journaled on the shaft and having oppositely extending arms projecting from the housing, a pair of tandem springs having adjacent ends engaging said arms, a horizontal perch carried by the housing, said perch being below and in spaced relation to said equalizer arms and extending sufficiently from the housing to be engageable by the adjacent ends of the springs in order to prevent inadvertent displacement of the springs from the arms.

2. In a tandem spring suspension unit; an equalizer housing bracket comprising a housing opening at opposite ends and including a pair of spaced side walls, a stud shaft extending between the side walls, an equalizer journaled on the shaft and having oppositely extending ar-ms projecting from the housing, a pair of tandem springs having adjacent ends engaging said arms, a horizontal perch connecting said side walls below the stub shaft, said perch being below and in spaced relation to the equalizer arms and having ends overlapping the adjacent ends of the springs to prevent inadvertent displacement of the springs from the arms, and means carried by the equalizer housing bracket below the perch for pivotally coupling the same to a torque rod.

3. A tandem spring suspension unit comprising an equalizer housing bracket consisting of a housing opening at opposite ends and adapted to be secured to a vehicle frame, a stub shaft in the housing, an equalizer centrally journaled on the shaft and having oppositely extending arms proof each of the springs for securing the same to an axle, a pair of torque arms below the springs, one of the torque arms having pivotal connection at one end with one of the spring hangers and at the other end with said springsecuring means nearest thereto, the other of said torque arms having pivotal connection at one end with the equalizer housing bracket and at the other end with the other of said spring securing means.

-4. The combination of claim 3, wherein at least one of the torque arms is adjustable in length.

5. A tandem spring suspension unit comprising an equalizer housing bracket consisting of a housing opening at opposite ends and adapted to be secured to a vehicle frame, a stub shaft in the housing, an equalizer centrally journaled on the shaft and having oppositely extending equalizer arms projecting from the housing, a pair of sprin hangers adapted to be secured to a vehicle frame and on opposite sides of the equalizer housing bracket, a pair of springs each one of which connects one of the hangers to one arm .of the equalizer, means carried centrally of each of the springs for securing the same to an axle, a pair of. torque arms below the springs, one of the torque arms having pivotal connection at one end with one of the spring hangers and at the other end with said means adjacent thereto, the

other of said torque arms having pivotal connection at one end with the equalizer housing bracket and at the other end with the other of said means, and a perch carried by the equalizer housing bracket below the stub shaft, said perch being below and in spaced relation to said equalizer arms and overlapping adjacent ends of the springs to prevent substantial displacement of the springs relative to the equalizer arms.

6. In a tandem spring suspension unit; a frame and a pair of spring hangers carried thereby, an equalizer housing bracket carried by the frame between the spring hangers, said bracket including a housing opening at opposite ends and a stub shaft secured therein, an equalizer journaled on the shaft and having oppositely extending arms projecting from the housing, a pair of springs in tandem, said hangers engaging the remote ends of the springs, the adjacent ends of the springs being in engagement with the arms of the equalizer, a perch fixed with respect to the housing and disposed below the adjacent ends of the springs for preventing inadvertent displacement of the springs from the arms, a pair of torque arms below said springs, means for pivotally securing the rear ends of the torque arms to the springs, means for pivotally connecting the forward end of one of the torque arms to the equalizer housing bracket, and means for pivotally connecting the forward end of the other torque arm to one of the spring hangers.

7, In a tandem spring suspension unit; a frame and a pair of spring hangers carried thereby, an equalizer housing bracket carried by the frame between the spring hangers, said bracket including a housing opening at opposite ends and a stub shaft secured therein, an equalizer journaled on the shaft and having oppositely extending arms projecting from the housing, a pair of springs in tandem, said hangers receiving the remote ends of the springs and having beveled wearing surfaces in engagement therewith, the adjacent ends of the springs being in engagement with the arms of the equalizer, a pair of torque arms below said springs, means for pivama 7 ntally se'cur'ing are l'ear'zends mf the itorque terms .to :the springs :means :Eorpivotally 'connecting the aforward end *of one (of :the :torqne arms "to the equalizer :honsing bracket, means -for ;pivota11y connecting dahe forward end iUf :the "other torque arm to "one of :the :spring hangers, and auperch :fixedly secured 1:0 the equalizer housing bracket.

below :the stub shaft, said much being disposed below rand inispacedi-relatidn :to thezadaiacent ends (of the springs and overlapping the adjacent ends :of the-springs for mreventing'displacement of the springs from the equalizer arms.

B. The zcombination of claim :7, wherein said last means includes a :pair :of .forward and downwardly extending legs integral with saidlon'e of ithe spring whangers, said 'othertorque *arm -heing pivotally received between the lower ends :f the 'legs.

'9. .A tandem spring suspension unit comprismg 'a pair of units secured to the side members :of :a wehicle frame, "each of :said units including a forward :and 'a rear :spring hanger and an equalizer :housing v bracket disposed fibetween .rsaid hangers, said equalizer housing comprising a pair of spaced side walls connected by :a stub ishaft, an equalizer journaled "on :said shaft and having a :pair of oppositely extending aarms,ta pair of springs in tandem arrangement and with each .of the springs connecting :one of the :spring hangers to the adjacent-arm of *thevequalizer, a perch connecting the :side walls :below the shaft and extending below the adjacent :ends "of @the springs,-a pair of .torquesarms each having .a inrward and a rear end, zone of said :torque relation thereto.

having i itsg-itorward aen'd pi-vntally nonnected :to the forward spring hanger and the-other torque having :forward end pivotally connected to the equalizer housing zbrac-ket rat a position below "the perch, :a spring chair secured to each of :said :springs, the rear ends of each of said torque arms being pivotally connected to the :spring chair immediately rearwardl-y thereof.

10.. The acombinationrof claim 9, wherein the torque arms of atleastoneef zsaid units are adjustabl'ein length.

:11. The :comhinationv'oi claim 19, wherein the spring hangers and the equalizer housing bracket 0f each of said sunits are secured .to the sides of saidframesideanembers. I

12. The combination of :claim 19,, wherein the spring hangers and the equalizer housing bracket 0f each =01 said units are vsecured to the under side :of said frame side members in depending VAN L. FRAZIER.

V REFERENCES crrno The following references are of record :in the file of ath-is lpatent:

UNITED STATES PA'IENTS 'Date "Ziegler May "23,1950 

